336 



University of California. 



[Vol. 3. 



the proportion of about ten to one for the Kern Canon. The 

 canon of the Kern was traversed after the writer had become 

 familiar with the kernbuts, and the walls were examined to dis- 

 cover what portions of them seemed likely to be affected by 

 slipping in future. A number of such places were fixed upon, 

 as, for instance, Tower Rock immediately opposite Coyote Creek. 

 But in none of these cases did it seem possible that a slip could 

 take place without sudden movement and catastrophic results. 

 In general, then, the kernbuts differ from land- and rock- slides 

 in not having been subjected to internal deformation or intense 

 shattering. They have been detached under other conditions than 

 those which attend such movements. 



Rift Hypothesis. — The alternative hypothesis, that the kern- 

 buts represent portions of wedges that have slipped down into an 

 opening rift along the line of the canon may next be examined. 

 This possibility may at first blush appear an extreme one to 

 entertain as an hypothesis explanatory of these remarkable feat- 

 ures. The theory of graben or dropt crustal blocks is, however, 

 so well established in geology that we have abundant analogy for 

 the suggestion and are, therefore, warranted in giving it serious 

 consideration. But the moment we attempt to apply this hypoth- 

 esis, we are confronted with the difficulty that we cannot con- 

 fine its application to these local features of the canon. The 

 hypothesis that the kernbuts are in any way due to the process 

 which gives rise to a graben involves the larger hypothesis that 

 the canon of the Upper Kern is itself in some sense a rift valley. 



Harmony of Kern Canon with Rift Hypothesis. — Now, certain 

 remarkable features of the canon lend themselves to this view. 

 These are : ( 1 ) The course of the canon is different from all the 

 other canons of the Sierra Nevada that are comparable with it in 

 size and character. These are, almost without exception, trenches 

 of streams which are consequent upon the general tilting of the 

 Sierra Nevada crust block, and flow westerly from the crest of 

 the range to the Great Valley of California. The Upper Kern 

 has on the contrary a meridional trend, parallel to the axis of 

 tilting, and lies but a few miles west of the great fault zone along 

 which the dislocation involved in the tilting occurred. (2) The 

 canon of the Upper Kern differs from all the other canons of the 



